In a content delivery system, operating in a wireless communication that utilizes a portable client and fixed server for delivery of audio and video content, protection and management of digital rights are a concern. Various methods are employed to efficiently deliver content such that digital rights of the content owner are protected. One conventional way to manage and protect the digital rights is to encrypt the content at the server using one or more keys (encryption or decryption) and providing the keys to an authorized user, using a client device, who subscribes to the content. Thus, the users with keys may decrypt the content to view and/or listen to subscribed content.
Generally, content is encrypted using keys (one or more bits) and the keys are delivered on a regular basis. The keys that decrypt the content are delivered periodically. In order to provide the content and keys that decrypt the content at client devices, various over the air techniques are used. Often, a key-exchange method is employed to provide a set of keys (for example public keys and private keys) between the server and the client.
A common method is for the client to request a new key(s) or server sending new key(s) to the client. According to this method, a new connection is made between client and server in order to transmit the keys to client. Depending on time of day, there could be several client devices on the system, each requesting a new set of keys. Responsive to the key requests, a new connection must be opened to exchange the keys. Most systems today require that new keys be used each time a new content is provided to the user, since using new keys provide a greater security. Also, each time one or more keys expire or each time a subscription is renewed, a new connection is created to update old or expired keys. This is a burden on system, considering that there are thousands of devices that may request access to new content or renew subscription. Opening and closing a connection ties up resources for the server, especially during peak hours. It would be useful to exchange keys without having to create a new connection and get the necessary keys to the client.
Therefore, an efficient delivery system is needed to deliver keys without placing an extra burden on the content delivery system.